Non-invasive visualisation and volume estimation of maggot masses using computed tomography scanning
- 382 Downloads
There is limited understanding of the actual temperatures that maggots experience during growth. The impact of maggot mass heating on their growth rates cannot be properly factored into maggot growth rate models, thus limiting the accuracy of forensic entomology estimates. One of the major factors contributing to mass heating is the mass size; however, measuring mass volume is problematic as masses quickly become disturbed when probing them to measure their depth and width. Furthermore, many masses are deep within the body cavity and are inaccessible. This study examined the development of a non-invasive means for measuring mass volume using computed tomography (CT) scanning. It was found that CT can be used to visualise and measure the volume of maggot masses, and a series of rules for doing so were established. The level of agreement between mass measurements made by four ‘judges’ using CT volumetric analysis tools produced excellent reliability (ICC > 0.95). This high level of reliability was maintained when applied to masses of different sizes in experimental cups of meat and natural masses of mixed species on human bodies. Entomological features of mortuary CT scans are now routinely reported in forensic entomology casework in Victoria, Australia, as a result of our work.
KeywordsForensic entomology Maggot mass Computed tomography Volume
This project was funded by ARC Linkage Grant LP0883711. We thank the Australian Federal Police and the NSW Police Force for their financial support, and the Victorian Institute of Forensic Medicine, the Victoria Police Force and Forensic Science SA for their in-kind support. We are also grateful to Dr. Marijka Batterham (UOW) for her assistance with the statistical analysis of the data.
Ethics approval for the use of CT scans of deceased was granted by the ethics committee of the Victorian Institute of Forensic Medicine.
Conflict of interest
The authors declare that they have no conflict of interest.
- 2.Girard M (1869) Etudes sur la chaleur libre degagee par les animaux invertebres et specialement les insectes. Ann Sci Nat Zool 11:135–274Google Scholar
- 3.Heinrich B (1993) The hot-blooded insects. Harvard University Press, CambridgeGoogle Scholar
- 5.Catts EP (1992) Problems in estimating the postmortem interval in death investigations. J Agric Entomol 9:245–255Google Scholar
- 7.Byrd JH, Castner JL (eds) (2010) Forensic Entomology: the utility of arthropods in legal investigations, 2nd edn. CRC Press, Bocs RatonGoogle Scholar
- 8.Greenberg B, Kunich JC (eds) (2002) Entomology and the law: flies as forensic indicators. Cambridge University Press, CambridgeGoogle Scholar
- 9.Goff ML (2000) A fly for the prosecution: how insect evidence helps solve crimes. Harvard University Press, LondonGoogle Scholar
- 10.Thali MJ, Dirnhofer R, Vock P (eds) (2009) The virtopsy approach: 3D optical and radiological scanning and reconstruction in forensic medicine. CRC Press Taylor & Francis Group, Boca RatonGoogle Scholar
- 12.Eisenhauer EA, Therasse P, Bogaerts J, Schwartz LH, Sargent D, Ford R, Dancey J, Arbuck S, Gwyther S, Mooney M, Rubinstein L, Shankar L, Dodd L, Kaplan R, Lacombe D, Verweij J (2009) New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1). Eur J Cancer 45:228–247PubMedCrossRefGoogle Scholar
- 13.Klaveren RJ, Oudkerk M, Prokop M, Scholten ET, Nackaerts K, Vernhout R, van Iersel CA, van den Bergh KAM, van’t Westeinde S, van der Aalst C, Thunnissen E, Xu DM, Wang Y, Zhao Y, Gietema HA, de Hoop B, Groen HJM, de Bock GH, Ooijen P, Weenink C, Verschakelen J, Lammers JJ, Timens W, Willebrand D, Vink A, Mali W, de Koning HJ (2009) Management of lung nodules detected by volume CT scanning. N Engl J Med 361:2221–2229PubMedCrossRefGoogle Scholar
- 14.Fleiss J (ed) (1986) The design and analysis of clinical experiments. John Wiley & Sons, New YorkGoogle Scholar
- 16.Burton JL (2008) Cellular injury. In: Raftery AT (ed) Applied basic science for basic surgical training, 2nd edn. Elsevier Limited, PhiladelphiaGoogle Scholar